1. Field of the Invention
The present invention relates in general to improved solar heat exchange systems and in particular to an improved solar heat exchange system which includes multiple parallel tubular elements. Still more particularly, the present invention relates to an improved solar heat exchange system having multiple parallel tubular elements each having a polygonal cross-section.
2. Description of the Prior Art
The utilization of solar energy to heat water for swimming pools and hydrotherapy tubs, in addition to residential and commercial water heating is well known. Traditionally, solar water heaters have been constructed utilizing metallic components, typically elongate metallic tubing which has been painted black to increase the heat absorption thereof. Such units are typically heavy and highly rigid in nature, expensive to fabricate and maintain and subject to damage as a result of freezing.
Recently, metallic tubes within solar heat exchangers have been replaced by mats of extruded elastomeric tubes which may be pre-colored black by including carbon black within the extrusion material. One example of such a product is described in Scholl, U.S. Pat. No. 3,648,768. Similar heat exchange systems are disclosed in U.S. Pat. No. 3,751,935, issued to MacCracken, U.S. Pat. No. 4,060,070, issued to Harter, and U.S. Pat. No. 4,709,689 issued to Simcox.
In the Scholl patent the elastomeric tubes are prepared for assembly by cutting away webs between the tubes and inserting the tubes onto a manifold. Various methods are then utilized to prevent the tubes from pulling out of the manifold including the utilization of flared screws, springs with tapered collars and heat-shrink end caps. Each of these methods requires the utilization of special tools and special skills.
The utilization of long tubular mats, each having a plurality of parallel tubes, is a clear advance in the solar heat exchange art; however, each of the tubes within such mats generally must be longitudinally separated from each adjacent tube, at least near the end portions, to permit the attaching of the tubes to a manifold. Typically, the tubes within such a mat are spaced by webbing in between the tubes and the webbing is torn manually to loosen the ends of the tube so that they may be connected to associated nipples on a header.
The Simcox patent discloses a technique for enhancing the efficiency of attaching such tubular mats to a manifold by utilizing a tubular header having radial holes bored therethrough and a one piece molded manifold having a base portion which extends over the radial bore within the header and which includes a plurality of radially aligned nipples protruding from the manifold base which may be attached to the tubular mat. Simcox teaches forcing the tubular ends within the mat over the nipples, and then joining all of the tubes on the mat to the manifold thereafter with a single motion. Assembly of the Simcox system is accomplished by applying adhesive to the base of the manifold and header and then aligning the manifold over the bores within the header and applying pressure.
While each of the aforementioned elastomeric mat solar heat exchange systems represents a substantial advance over the metallic elements utilizing in prior art systems, the amount of solar energy which may be obtained from all such mats is substantially identical. Studies within the solar heat exchange art have shown that maximum efficiency in increasing the temperature of water within such mats is achieved by the irradiation of those mats by solar radiation at a particular optimal angle. However, the exigencies of mounting these mats on rooftops or other existing structures often prevents the placement of the mat in a manner which might otherwise maximize the receipt of solar energy. Additionally, the tubular nature of the elements within these mats often acts to reflect solar energy away from the mat, in response to nonoptimal radiation by solar energy.
It should therefore be apparent that a need exists for an improved solar heat exchange system which greatly enhances the efficiency of solar radiation absorption within the elastomeric mat collector.